69 research outputs found

    Pollution sources in Cunha Baixa uranium mining area (Viseu, Portugal)

    Get PDF
    [Abstract] One of the most significant environmental issues that have arisen in the abandoned Cunha Baixa uranium mine area is the Acid Drainage (AD). Downward the mining site AD affects surface and irrigation water quality. ln order to evaluate their contribution as a pollution source, this paper discusses: i) the composition of mine water, pit lake water and effluent water discharged after chemical treatment and settling, and ii) the conrribution of rocks and mine wastes as acid generators materials. Pit lake and mine waters are acidic (pH 3- 4) with high 226 Ra activity (1.8-12 Bq/l), sulphate (1000-2400 mg/l) and heavy metals concentration (Al: 8-70 mg/l; Mn: 4-35 mg/l; Fe: 1-55 mg/l; U: 1.2-6.3 mg/l; Zn: 0.5-2.9 mg/l). ln spite of mine water treatment and settling efficiency to remove the main dissolved species (50-80 %), the overflow effluent can be a source of pollution, due to high contents of sulphate, uranium as well fluorine and calei um. The chemical treatment was also responsible for the water hardness in this granitic region. Rocks and mine wastes submitted to static and kinetic laboratory tests (Acid-Base accounting test and Humidity Cell test) did not show capacity to generate acid drainage from sulphide oxidation through testing rime, nevertheless Thiobacillus ferrooxidans bacterium was detected in mine waters. However, the open pit wastes showed low acid neutralising potential and capacity to generate an acid leachate (pH < 5) with potentialities to release sulphate and heavy metals. The running water or the pit lake water percolating through these wastes was able to mobilise elements and increase its dispersion by contínuos contaminating leaching. The acid drainage in Cunha Baixa can be the remaining result of heap leaching process used in past, to recover uranium from low-grade ore when opening the pit area, although this process ceased in 1993

    Impacts on water, soil and plants from the abandoned Miguel Vacas copper mine, Portugal

    Get PDF
    Soil, water and plant geochemistry was studied around the Miguel Vacas copper mine (Alentejo, SE Portugal), which stopped its exploitation and processing activities in 1991. After closure waste-rock piles remained exposed to weathering. The copper ore was mainly composed of copper phosphates and carbonates. Remediation actions were insufficient to prevent the spreading of waste-rock materials to surrounding farmed fields. The latter caused contamination of soils and water. Based on overall characteristics water from wells and surface stream water mostly can be classified as of the sulphate magnesium type. The application of a chemical equilibrium model to the sampled water showed that copper, phosphate and sulphate concentrations are controlled by copper(II) secondary minerals (pseudomalachite, libethenite and malachite) and gypsum. Nevertheless, groundwater can be used for irrigation and cattle based on quality parameters. Soils and plants (Prunus domestica L., Olea europaea L. spp. europaea and Quercus ilex L.) were collected southeast of the open pit and the exploitation substructures. The soils located in the influence of drainage water that percolated through waste material or exploitation substructures were contaminated with Cu, and Ni was close to the maximum value allowed by Portuguese legislation. These soils, however, did not show elevated Zn and Mn concentrations. The trace element content in plants was within the normal range, with Q. ilex being able to accumulate Mn and to some extent also Ni. Dispersion of trace elements seemed to be limited to a distance 1500 m down from the waste dumps in southeastern direction

    Efeitos de um programa de 12 semanas de Hidroginástica na postura corporal de mulheres de meia-idade

    Get PDF
    À medida que a população mundial envelhece, sérias preocupações são levantadas sobre o efeito do exercício físico e de aptidão física para a saúde pública, especialmente na meia e terceira idade (Cruz-Ferreira et al., 2011). Os programas de exercícios aquáticos ganharam popularidade devido à diminuição de hipotéticos pacientes (i.e. ajudam na prevenção de patologias), e até mesmo entre indivíduos saudáveis (Costa et al., 2011). Ambos os programas, terrestres e aquáticos, baseiam-se no objetivo de alcançar e manter um nível adequado de aptidão física (incluindo a postura corporal) e, portanto, melhorar a qualidade de vida. A postura corporal tem em consideração a oscilação e/ou o alinhamento do corpo. O alinhamento do corpo representa a posição do corpo e a relação espacial entre os seus segmentos anatómicos para manter o equilíbrio, em condições estáticas ou dinâmicas, de acordo com os requisitos do ambiente e da tarefa motora. Um alinhamento adequado do corpo envolve o menor esforço (i.e. gasto energético) e sobrecarga mecânica, para otimizar a eficiência do sistema biológico. Uma postura corporal incorreta pode estar relacionada com alguma desordem a nível ortopédico (Kristensen, Bandholm, Holm, Ekdahl, & Kehlet, 2009), músculo-esquelético (Oyarzo, Villagrán, Silvestre, Carpintero, & Berral, 2013) ou neurológico (Busse, Zimdars, Zalewski, & Steffen, 2005), mas também associada com uma maior probabilidade de quedas (Sakamoto et al., 2006).info:eu-repo/semantics/publishedVersio

    Uranium distribution in the solid phases of soils from Cunha Baixa mining site (Portugal)

    Get PDF
    The present study concerns the application of partial chemical extraction, in a parallel procedure, to evaluate the uranium distribution in different solid phases constituents of the soils in the vicinity of Cunha Baixa mining area in order to assess its environmental risk. In the surface horizon of the soils, uranium that reached total concentrations between 9.8 to 362 mg/kg was preferential bound to non-crystalline iron oxides. These phases represent a small environmental risk. The contaminated irrigation water (>100 μg U/L) and the exchangeable complex of the acidic soils (pH <5), are important sources for the available fraction of uranium for crops (up to 30% of total U). The transference of uranium into the soil-water-plant system could be a factor of risk for Cunha Baixa population through the ingestion of vegetal foodstuffs, due to its possible uranium bioaccumulation capacity

    Efeito de um programa de 12 semanas de hidroginástica na postura corporal de mulheres de meia-idade

    Get PDF
    À medida que a população mundial envelhece, sérias preocupações são levantadas sobre o efeito do exercício físico e de aptidão física para a saúde pública, especialmente na meia e terceira idade (Cruz Ferreira et al., 2011). Os programas de exercícios aquáticos ganharam popularidade devido à diminuição de hipotéticos pacientes (i.e. ajudam na prevenção de patologias), e até mesmo entre indivíduos saudáveis (Costa et al., 2011) . Ambos os programas, terrestres e aquáticos, baseiam-se no objetivo de alcançar e manter um nível adequado de aptidão física (incluindo a postura corporal) e, portanto, melhorar a qualidade de vida.info:eu-repo/semantics/publishedVersio

    Trasplante cardíaco

    Get PDF
    A heart transplant is at present considered the treatment of choice in cases of terminal cardiac insufficiency refractory to medical or surgical treatment. Due to factors such as the greater life expectancy of the population and the more efficient management of acute coronary syndromes, there is an increasing number of people who suffer from heart failure. It is estimated that the prevalence of the disease in developed countries is around 1%; of this figure, some 10% are in an advanced stage and are thus potential receptors of a heart transplant. The problem is that it is still not possible to offer this therapeutic form to all of the patients that require it. Consequently, it is necessary to optimise the results of the heart transplant through the selection of patients, selection and management of donors, perioperative management and control of the disease due to graft rejection. Since the first transplant carried out in 1967, numerous advances and changes have taken place, which has made it possible to increase survival and quality of life of those who have received a new heart. In this article we review the most relevant aspects of the heart transplant and the challenges that are currently faced

    A Nearly Linear-Time PTAS for Explicit Fractional Packing and Covering Linear Programs

    Get PDF
    We give an approximation algorithm for packing and covering linear programs (linear programs with non-negative coefficients). Given a constraint matrix with n non-zeros, r rows, and c columns, the algorithm computes feasible primal and dual solutions whose costs are within a factor of 1+eps of the optimal cost in time O((r+c)log(n)/eps^2 + n).Comment: corrected version of FOCS 2007 paper: 10.1109/FOCS.2007.62. Accepted to Algorithmica, 201

    Compilation of parameterized seismogenic sources in Iberia for the SHARE European-scale seismic source model.

    Get PDF
    Abstract: SHARE (Seismic Hazard Harmonization in Europe) is an EC-funded project (FP7) that aims to evaluate European seismic hazards using an integrated, standardized approach. In the context of SHARE, we are compiling a fully-parameterized active fault database for Iberia and the nearby offshore region. The principal goal of this initiative is for fault sources in the Iberian region to be represented in SHARE and incorporated into the source model that will be used to produce seismic hazard maps at the European scale. The SHARE project relies heavily on input from many regional experts throughout the Euro-Mediterranean region. At the SHARE regional meeting for Iberia, the 2010 Working Group on Iberian Seismogenic Sources (WGISS) was established; these researchers are contributing to this large effort by providing their data to the Iberian regional integrators in a standardized format. The development of the SHARE Iberian active fault database is occurring in parallel with IBERFAULT, another ongoing effort to compile a database of active faults in the Iberian region. The SHARE Iberian active fault database synthesizes a wide range of geological and geophysical observations on active seismogenic sources, and incorporates existing compilations (e.g., Cabral, 1995; Silva et al., 2008), original data contributed directly from researchers, data compiled from the literature, parameters estimated using empirical and analytical relationships, and, where necessary, parameters derived using expert judgment. The Iberian seismogenic source model derived for SHARE will be the first regional-scale source model for Iberia that includes fault data and follows an internationally standardized approach (Basili et al., 2008; 2009). This model can be used in both seismic hazard and risk analyses and will be appropriate for use in Iberian- and European-scale assessments
    corecore